Home |
Search |
Today's Posts |
#1
Posted to rec.audio.tech
|
|||
|
|||
Condenser microphones and water?
The following message was displayed prominently on the exterior of the box to
the Gold Edition MXL V67G microphone I bought: CAUTION All condenser microphones are very sensitive to moisture. For close vocal use, MXL strongly recommends the use of a pop filter or foam wind screen to prevent permanent damage to the transducer. which makes me wonder if condenser microphones have a limited lifespan in general, just from the humidity in the air. Is this something I should worry about? If it is, what can I do about it? I have heard of some people protecting their microphones by sticking them in rubber balloons. I don't live in a sunny state, I live in Portland, Oregon, and the summer is over, and we are proceeding into our rainy season. |
#2
Posted to rec.audio.tech
|
|||
|
|||
Condenser microphones and water?
Im_Beta_00 wrote:
The following message was displayed prominently on the exterior of the box to the Gold Edition MXL V67G microphone I bought: CAUTION All condenser microphones are very sensitive to moisture. For close vocal use, MXL strongly recommends the use of a pop filter or foam wind screen to prevent permanent damage to the transducer. which makes me wonder if condenser microphones have a limited lifespan in general, just from the humidity in the air. Is this something I should worry about? If it is, what can I do about it? I have heard of some people protecting their microphones by sticking them in rubber balloons. I don't live in a sunny state, I live in Portland, Oregon, and the summer is over, and we are proceeding into our rainy season. Moisture of any kind, and particularly "conductive" moisture like breath condensation will short out the ultra-high impedance of the condenser capsule and wiring. Even partial shorting of this high- impedance node will cause significant noise and loss of signal. That is the primary vulnerability of condenser mics to moisture. Unless the water leaves conductive residue behind, once the moisture is gone, no permanent damage remains. However a secondary mode of long-term deterioration is leaving the surfaces sticky and more prone to collecting and holding dust, etc. from the air. This may be the "permanent damage" MXL is referring to. It can be cleaned, but it is a delicate operation best done by skilled and experienced technicians, and so maybe beyond the cost/benefit of fixing a low-cost microphone. I also live in the Portland metro area (Hillsboro) and I am not concerned about ambient humidity harming any of my many condenser microphones. |
#3
Posted to rec.audio.tech
|
|||
|
|||
Condenser microphones and water?
Richard Crowley wrote:
Im_Beta_00 wrote: snip which makes me wonder if condenser microphones have a limited lifespan in general, just from the humidity in the air. Is this something I should worry about? If it is, what can I do about it? I have heard of some people protecting their microphones by sticking them in rubber balloons. I don't live in a sunny state, I live in Portland, Oregon, and the summer is over, and we are proceeding into our rainy season. Moisture of any kind, and particularly "conductive" moisture like breath condensation will short out the ultra-high impedance of the condenser capsule and wiring. Even partial shorting of this high- impedance node will cause significant noise and loss of signal. That is the primary vulnerability of condenser mics to moisture. Unless the water leaves conductive residue behind, once the moisture is gone, no permanent damage remains. However a secondary mode of long-term deterioration is leaving the surfaces sticky and more prone to collecting and holding dust, etc. from the air. This may be the "permanent damage" MXL is referring to. It can be cleaned, but it is a delicate operation best done by skilled and experienced technicians, and so maybe beyond the cost/benefit of fixing a low-cost microphone. I also live in the Portland metro area (Hillsboro) and I am not concerned about ambient humidity harming any of my many condenser microphones. Hate to confess it, but I am a teensy bit hard of hearing. Is there any software that will let me 'see' what the difference is, between a new microphone, and one that has been compromised? I mean, compromised from the accumulation of grease and dirt after the water has evaporated. Not only that, but I was wondering about the possibility of those little metal ribbons inside condenser microphones. Do they ever corrode? Which software do you suggest for generating a sound spectrograph? My setup, is an unexpanded Mac mini, and the aforementioned MXL V67G microphone. It may seem a little old-fashioned, but I was thinking of using a tuning fork at about a foot's distance, and set my Fostex FR-2LE's gain more or less to the middle. Would that work? |
#4
Posted to rec.audio.tech
|
|||
|
|||
Condenser microphones and water?
Im_Beta_00 wrote:
Hate to confess it, but I am a teensy bit hard of hearing. Is there any software that will let me 'see' what the difference is, between a new microphone, and one that has been compromised? I mean, compromised from the accumulation of grease and dirt after the water has evaporated. If the noise or distortion is audible and detracts from the signal you are recording, then it is compromised. Not only that, but I was wondering about the possibility of those little metal ribbons inside condenser microphones. Do they ever corrode? Little metal ribbons inside condenser microphones? I don't know what you mean. Condenser microphones typically have a round diaphragm of stretched plastic. The diaphragm has been made conductive by some method such as metal evaporation or sputtering, etc. Very early models (mid 20th century) used kinds of plastic that weren't long-term stable, but modern mics have life expectancy of many decades, minimum. Failure modes include any kind of mechanical trauma, or the diaphragm picking up mass from debris stuck to it (and causing it to lose sensitivity), or dirt and/or moisture causing shorting or leakage of the very high impedance node. Dynamic microphones usually have stamped or molded plastic diaphragms onto which the wire coil is glued, etc. In addition to physical trauma, dynamic mics sometimes collect ferrous (magnetic) metal bits which are attracted and held by the strong magnetic field. The only kinds of mics that have "little metal ribbons" are ribbon mics which have a very thin ribbon of aluminum suspended inside a strong magnetic field. In addition to attracting and holding metal debris, ribbon mics have a failure mode of the ribbon stretching and/or breaking from strong wind or dropping, etc. Which software do you suggest for generating a sound spectrograph? My setup, is an unexpanded Mac mini, and the aforementioned MXL V67G microphone. It may seem a little old-fashioned, but I was thinking of using a tuning fork at about a foot's distance, and set my Fostex FR-2LE's gain more or less to the middle. Would that work? What software are you using? Does it make a specgtrograph? Once you have your spectrograph, how do you know if it is good or bad? I would start by characterizing the audio chain. First the A/D converter, then the mic preamp and cable, and finally the microphone itself. How much noise is there and what does it sound and look like? If you know how much noise you are getting without the mic plugged in, then you know how much the microphone is contributing. If you are testing for noise, you need the quietest place you can find. You could try waiting until 3am and burrying the mic in a big pile of bedding and pillows, etc. Conider that you may be obsessing about something that probably doesn't make the top 100 things to worry about. |
#5
Posted to rec.audio.tech
|
|||
|
|||
Condenser microphones and water?
Im_Beta_00 wrote:
The following message was displayed prominently on the exterior of the box to the Gold Edition MXL V67G microphone I bought: CAUTION All condenser microphones are very sensitive to moisture. For close vocal use, MXL strongly recommends the use of a pop filter or foam wind screen to prevent permanent damage to the transducer. Common sense. which makes me wonder if condenser microphones have a limited lifespan in general, just from the humidity in the air. No. Is this something I should worry about? No. If it is, what can I do about it? At the price point of the mic in question use it for target practice. I have heard of some people protecting their microphones by sticking them in rubber balloons. You have overlooked one word frequently found in humidity specs "non condensing", ie. water droplets may not be allowed to form on the object. That would just keep condensation moisture contained. A cloth bag or a paper envelope does a a great job of keeping particle contamination away from a mic that is left on a micstand permanently in studio, I recall some fairly long thread about which mediocre whisky that comes in the best bag for the purpose of storing a mic. I don't live in a sunny state, I live in Portland, Oregon, and the summer is over, and we are proceeding into our rainy season. Put the mic on phantom power a day before you will use it, that is what I do. If you are a studio then build a mic cupboard with connectors that supply phantom power and keep the mics powered up permanently while stored. To evaluate a microphone or compare microphones: record speech, it is an excellent test signal. To evaluate in a year .... guess what ... To evaluate in 10 years .... guess what ... Kind regards Peter Larsen |
#6
Posted to rec.audio.tech
|
|||
|
|||
Condenser microphones and water?
Peter Larsen wrote:
Im_Beta_00 wrote: snip which makes me wonder if condenser microphones have a limited lifespan in general, just from the humidity in the air. No. Is this something I should worry about? No. If it is, what can I do about it? At the price point of the mic in question use it for target practice. Um, okay. I have heard of some people protecting their microphones by sticking them in rubber balloons. You have overlooked one word frequently found in humidity specs "non condensing", ie. water droplets may not be allowed to form on the object. That would just keep condensation moisture contained. A cloth bag or a paper envelope does a a great job of keeping particle contamination away from a mic that is left on a micstand permanently in studio, I recall some fairly long thread about which mediocre whisky that comes in the best bag for the purpose of storing a mic. Hmmm. Is that because high proof whiskey yields alcoholic vapors that don't harm the microphone? I don't live in a sunny state, I live in Portland, Oregon, and the summer is over, and we are proceeding into our rainy season. Put the mic on phantom power a day before you will use it, that is what I do. If you are a studio then build a mic cupboard with connectors that supply phantom power and keep the mics powered up permanently while stored. That would warm up the microphone, and make the moisture evaporate? To evaluate a microphone or compare microphones: record speech, it is an excellent test signal. Well, I am not yet deaf as a stone, but I think a sound spectrograph would be better. To evaluate in a year .... guess what ... To evaluate in 10 years .... guess what ... Kind regards Peter Larsen Thanks. |
#7
Posted to rec.audio.tech
|
|||
|
|||
Condenser microphones and water?
Im_Beta_00 wrote:
in studio, I recall some fairly long thread about which mediocre whisky that comes in the best bag for the purpose of storing a mic. Hmmm. Is that because high proof whiskey yields alcoholic vapors that don't harm the microphone? No, because the cloth bag the cheap whisky body is sold in looks great in a studio. Put the mic on phantom power a day before you will use it, that is what I do. If you are a studio then build a mic cupboard with connectors that supply phantom power and keep the mics powered up permanently while stored. That would warm up the microphone, and make the moisture evaporate? Erm ... climate here in Copenhagen is not dissimilar from where you are. I don't think there is a problem with condensing moisture that matters inside a warmed up building. I suggest it because I often notice on location that microphones tend to open up sonically after having been powered up for more than one hour. It may be less wise to keep a valve type microphone powered up constantly, also from a CO2 point of view, those I have come with a high voltage power supply. To evaluate a microphone or compare microphones: record speech, it is an excellent test signal. Well, I am not yet deaf as a stone, but I think a sound spectrograph would be better. Surprise surprise, it can tell you how a microphone measures, but not how it sounds and not how the measurement correlates with the percieved sound of the mic. It is the same problem as with loudspeakers ... one factor is directivity and the other is delayed resonance, ie. a resonance that causes only minor - if any - change of measured frequency response but - by sound in that range decaying slower than the rest of the audio range - generates a noticeable colouration of the sound. A spectogram can tell you, if you have a repeatable sound source, whether the mic has changed. To evaluate a microphones sound speech and a the rattle bundle of keys has excellent mileage - as has a piano quartett using a full size concert grand. Thanks In the real world of recording microphone positioning matters more than minor sonic variations between microphones, the mileage of an inch of movement of a pair used for an ensemble can be surprising if that inch of movement takes your mic away from a "bad" reflection from the ceiling. Worry less, record more, learn, enjoy! Kind regards Peter Larsen |
#8
Posted to rec.audio.tech
|
|||
|
|||
Condenser microphones and water?
I recall some fairly
long thread about which mediocre whisky that comes in the best bag for the purpose of storing a mic. Hmmm. Is that because high proof whiskey yields alcoholic vapors that don't harm the microphone? Or because whiskey is good for drinking and aids in creativity? |
#9
Posted to rec.audio.tech
|
|||
|
|||
Condenser microphones and water?
Peter Larsen wrote:
Im_Beta_00 wrote: Well, I am not yet deaf as a stone, but I think a sound spectrograph would be better. Surprise surprise, it can tell you how a microphone measures, but not how it sounds I think that's exactly what it /does/ measure. and not how the measurement correlates with the percieved sound of the mic. It is the same problem as with loudspeakers ... one factor is directivity and the other is delayed resonance, ie. a resonance that causes only minor - if any - change of measured frequency response but - by sound in that range decaying slower than the rest of the audio range - generates a noticeable colouration of the sound. A spectogram can tell you, if you have a repeatable sound source, whether the mic has changed. To evaluate a microphones sound speech and a the rattle bundle of keys has excellent mileage - as has a piano quartett using a full size concert grand. Thanks In the real world of recording microphone positioning matters more than minor sonic variations between microphones, the mileage of an inch of movement of a pair used for an ensemble can be surprising if that inch of movement takes your mic away from a "bad" reflection from the ceiling. Worry less, record more, learn, enjoy! I stumbled on an old issue (March 1995) of Video Toaster magazine (unfortunately never having had the pleasure of owning an Amiga, let alone a Video Toaster to go along with it), and Cliff Roth suggested on page 24 that, in recording a four man band, you really ought to have four microphones just for the drums, and probably a pair of microphones for every performer. Placing four microphones by a drum necessarily involves different distances from the drum. I suppose that would all be well and good, but another book I have, says you should have microphones positioned on the sources of noise (such as unwanted echoes, or maybe even traffic noise), just so you can subtract them (one or more times) from the sound that you are actually trying to record. I am not trying to digress. I understand what you mean by carefully positioning your microphones in one place or another, and taking pains to record separate tracks of the unwanted noise for no other purpose than subtraction, but this is difficult for a person to reckon properly if his hearing is already going. And while I am on the subject of maintaining separate files of sound, are there any programs that let you manipulate them with 128 bit integers (not floating point). When I scope around for software that will let me manage my sound files, these files being raw files, you'd think they would realize that floating point admits errors, just as 128 bit integer math does. But I have yet to see a detailed discussion of what raw data really looks like (you know, in terms of a hex dump). I wasn't being facetious when I suggested the usefulness of sound spectrographs. For people who are beginning to go deaf, this sort of thing is essential to understand what we are dealing with. Not all sound spectrographs are the same. They represent well-ordered collections of "extracted frequencies" indexed by a time rate (milliseconds is pretty common, I understand) and an intensity level such as volume. |
#10
Posted to rec.audio.tech
|
|||
|
|||
Condenser microphones and water?
Im_Beta_00 wrote:
Peter Larsen wrote: Im_Beta_00 wrote: Well, I am not yet deaf as a stone, but I think a sound spectrograph would be better. Surprise surprise, it can tell you how a microphone measures, but not how it sounds I think that's exactly what it /does/ measure. Your sentiment is not shared by acknowledged experts, but you are free to think what you wish. I stumbled on an old issue (March 1995) of Video Toaster magazine (unfortunately never having had the pleasure of owning an Amiga, let alone a Video Toaster to go along with it), and Cliff Roth suggested on page 24 that, in recording a four man band, you really ought to have four microphones just for the drums, and probably a pair of microphones for every performer. Placing four microphones by a drum necessarily involves different distances from the drum. I'm sure that Mr. Roth has brought some enlightment about audio to the amateur videographers who read Video Toaster magazine. Neither the author nor the magazine are noted as having any kind of expertiese or authority on the art or technology of audio. There are more different ways of micing a 4-man band (and even a drum kit) than there are people on the planet. I suppose that would all be well and good, but another book I have, says you should have microphones positioned on the sources of noise (such as unwanted echoes, or maybe even traffic noise), just so you can subtract them (one or more times) from the sound that you are actually trying to record. I am not trying to digress. I understand what you mean by carefully positioning your microphones in one place or another, and taking pains to record separate tracks of the unwanted noise for no other purpose than subtraction, but this is difficult for a person to reckon properly if his hearing is already going. It would be nice if you could do that. But nobody has ever discovered a successful method of applying it. Even people with extraordinary hearing. If you find a way of doing that, the Hollywood studios alone would pay millions of $$ for the process. And while I am on the subject of maintaining separate files of sound, are there any programs that let you manipulate them with 128 bit integers (not floating point). 128 bits of dynamic range would destroy the universe as we know it. Humans with perfect hearing can handle around 100dB of dynamic range. 16-bits = 96 dB and is better than anything any of us can hear in the real world. When I scope around for software that will let me manage my sound files, these files being raw files, What does "manage" mean? What does "raw" mean? It is very unlikely that you have "raw" files. But since you have revealed nothing about where they came from or how you created them, we can only guess that they are likely 16-bit linear uncompressed files (like "wav", et. al.). Or maybe they are compressed files like MP3, et.al.? you'd think they would realize that floating point admits errors, just as 128 bit integer math does. Brownian motion of the air between the source and the mic, along with the noise that one finds everywhere outside the most pefect anechoic chamber introduce at least 10x more "error" than even 32-bit floating point arithmetic. That is why nobody bothers with any larger bit-depth for conventional audio recording or processing. But I have yet to see a detailed discussion of what raw data really looks like (you know, in terms of a hex dump). The format of audio files is well documented and easily available. But first you must identify exactly what kind of files you have. I wasn't being facetious when I suggested the usefulness of sound spectrographs. For people who are beginning to go deaf, this sort of thing is essential to understand what we are dealing with. Not all sound spectrographs are the same. They represent well-ordered collections of "extracted frequencies" indexed by a time rate (milliseconds is pretty common, I understand) and an intensity level such as volume. The debate between measurement and perception has been raging for decades. You are pretty late to that party. Good luck. |
#11
Posted to rec.audio.tech
|
|||
|
|||
Advice needed (was 'condensing water on microphones')
Richard Crowley wrote:
Im_Beta_00 wrote: I suppose that would all be well and good, but another book I have, says you should have microphones positioned on the sources of noise (such as unwanted echoes, or maybe even traffic noise), just so you can subtract them (one or more times) from the sound that you are actually trying to record. I am not trying to digress. I understand what you mean by carefully positioning your microphones in one place or another, and taking pains to record separate tracks of the unwanted noise for no other purpose than subtraction, but this is difficult for a person to reckon properly if his hearing is already going. It would be nice if you could do that. But nobody has ever discovered a successful method of applying it. But they must have come close, or nobody would ever have bothered to write it down in a book for me to stumble on? Even people with extraordinary hearing. If you find a way of doing that, the Hollywood studios alone would pay millions of $$ for the process. Wait! Are you suggesting I shouldn't even try that? As you can tell, I am a beginner. (Even you were a beginner once.) I am going to shoot a digital film using the following setup: Fostex FR-2LE (stereo recording mode turned on) input #1 SGM-2X shotgun microphone on boom input #2 R0de NTG-1 shotgun microphone somewhat farther away, maybe a good 10 feet away, in a cross direction, mounted on a tripod that is stationary. Edirol R-09HR (an inexpensive stereo recorder) input #3 SMX-10 directional stereo microphone mounted on a tripod, about 20 to 30 feet away, pointed solely at the expected source of noise, a street that is usually empty, but you never can tell. Input #2 and Input #3 are pointed directly away from each other; they are in a straight line with the cast; if the 3rd file is subtracted from the 2nd file, there ought to be an ordinary ambient background, i.e., a reference level, in a manner of speaking, against which to mix the sound recorded in the 1st file. The sole purpose of the cheapie Edirol R-09HR is to pick up whatever street noise there might be, for subtracting (possibly several times) from the dialog. One problem, is that the Edirol R-09HR will be going continuously, as it is not synchronized to the clap of the slate. We don't have the luxory of shutting down the street, and I was hoping I could just pick up all the crappy exterior noise as "back noise" for use as the mask to filter with, later on. I have additional recorders but no reel to reel recorders. And so far as I can tell, the recorders I /am/ using, have no time codes stored in the course of the recording process. So I am making do, with what I have at my disposal. |
#12
Posted to rec.audio.tech
|
|||
|
|||
Advice needed (was 'condensing water on microphones')
On 10/10/2009 2:33 PM Im_Beta_00 spake thus:
I am going to shoot a digital film using the following setup: Fostex FR-2LE (stereo recording mode turned on) input #1 SGM-2X shotgun microphone on boom input #2 R0de NTG-1 shotgun microphone Edirol R-09HR (an inexpensive stereo recorder) input #3 SMX-10 directional stereo microphone mounted on a tripod, about 20 to 30 feet away, pointed solely at the expected source of noise, a street Well, it's plain enough to see what you're *trying* to do here, especially with your second "noise-cancelling" recorder. DISCLAIMER: IANARE (I am not a recording expert) However, I can still tell you with confidence that it ain't gonna work. Fuggedaboudit. Since you're using 2 completely unsyncrhonized recorders, there's no way in hell you're ever going to get that second recorder's sound to cancel ambient noise picked up by the first recorder. Think about it a second or three and I'm sure you'll agree. Being even a millisecond or so within synch isn't close enough. And here you've got two recorders, one an admittedly "cheap" one, and no time codes. Noise cancelling is a whole 'nother can of worms altogether. Attempting it on the cheap as you're proposing is futile. The experts here can add lots more. -- Found--the gene that causes belief in genetic determinism |
#13
Posted to rec.audio.tech
|
|||
|
|||
Advice needed (was 'condensing water on microphones')
Im_Beta_00 wrote:
Richard Crowley wrote: Im_Beta_00 wrote: I suppose that would all be well and good, but another book I have, says you should have microphones positioned on the sources of noise (such as unwanted echoes, or maybe even traffic noise), just so you can subtract them (one or more times) from the sound that you are actually trying to record. I am not trying to digress. I understand what you mean by carefully positioning your microphones in one place or another, and taking pains to record separate tracks of the unwanted noise for no other purpose than subtraction, but this is difficult for a person to reckon properly if his hearing is already going. It would be nice if you could do that. But nobody has ever discovered a successful method of applying it. But they must have come close, or nobody would ever have bothered to write it down in a book for me to stumble on? Don't believe everything you read in a book. The facts speak for themselves. And acoustic physics backs it up. Even people with extraordinary hearing. If you find a way of doing that, the Hollywood studios alone would pay millions of $$ for the process. Wait! Are you suggesting I shouldn't even try that? Knock yourself out. We won't expect any progress reports. As you can tell, I am a beginner. (Even you were a beginner once.) Perhaps you will learn something then. Acoustical physics. Like gravity, its the law. You'd have better luck inventing a perpetual motion machine. Suggest enrolling yourself for college physics. Then at least you will get some sort of credit for conducting the experiment. OTOH, the professor probably won't allow it. |
#14
Posted to rec.audio.tech
|
|||
|
|||
Advice needed (was 'condensing water on microphones')
David Nebenzahl wrote:
On 10/10/2009 2:33 PM Im_Beta_00 spake thus: snip Since you're using 2 completely unsyncrhonized recorders, there's no way in hell you're ever going to get that second recorder's sound to cancel ambient noise picked up by the first recorder. Firstly, whenever you are dealing with a recorder that has no time codes, and I assume that none of the recorders listed have time codes, you are going to find yourself doing some "hand-synchronizing" in post. I am not so nuts that I would even *think* of mixing any of this stuff live. I need an ambient background that serves as a "reference" level against which to mix the foreground. Secondly, this is an area roughly 3 acres in area. Just about every direction from the shooting site is thick with trees (good for damping out the really obnoxious stuff) except for that 80 foot driveway that comes from the sporadically trafficked street road, where we expect the noise to be coming from. That short little road is where the noise-cancelling recorder is going to be. The cast is much farther away from the road. The ambient noise of the wind, whatever it is, is going to be that much worse, and potentially unsolvable, as we are going to be more or less at the top of a mountain, even with windscreens on *all* of the mikes. It's not like we are looking to record the sound of a proverbial pin dropping on the floor. (And we are going to be mixing in some light background music to prevent people from hearing the pin dropping on the floor, anyways.) So, what we are actually concerned with, is the dialog of the cast, minus the occasional car (50 or 60 feet away from the cast, maybe even 80 feet away) zooming by. Well, some of this depends on how "loud" the noise is. We won't be able to cancel all of it, but some of it is bound to be useful. Think about it a second or three and I'm sure you'll agree. Being even a millisecond or so within synch isn't close enough. If I am within a millisecond, I am going to be doing a whole lot better than if I were doing it a quarter second off. I expect to reduce the street noise to a manageable sound level, maybe one fourth the sound level of the cast. That means that not all of the noise can be subtracted out, but some of it ought to be subtractable. |
#15
Posted to rec.audio.tech
|
|||
|
|||
Advice needed (was 'condensing water on microphones')
Im_Beta_00 wrote:
David Nebenzahl wrote: On 10/10/2009 2:33 PM Im_Beta_00 spake thus: snip Since you're using 2 completely unsyncrhonized recorders, there's no way in hell you're ever going to get that second recorder's sound to cancel ambient noise picked up by the first recorder. It wouldn't matter if you were recording on the SAME multi track recorder. The laws of acoustics and physics deny any known solution at this time. Firstly, whenever you are dealing with a recorder that has no time codes, and I assume that none of the recorders listed have time codes, you are going to find yourself doing some "hand-synchronizing" in post. I am not so nuts that I would even *think* of mixing any of this stuff live. I need an ambient background that serves as a "reference" level against which to mix the foreground. Secondly, this is an area roughly 3 acres in area. Just about every direction from the shooting site is thick with trees (good for damping out the really obnoxious stuff) except for that 80 foot driveway that comes from the sporadically trafficked street road, where we expect the noise to be coming from. That short little road is where the noise-cancelling recorder is going to be. The cast is much farther away from the road. The ambient noise of the wind, whatever it is, is going to be that much worse, and potentially unsolvable, as we are going to be more or less at the top of a mountain, even with windscreens on *all* of the mikes. It's not like we are looking to record the sound of a proverbial pin dropping on the floor. (And we are going to be mixing in some light background music to prevent people from hearing the pin dropping on the floor, anyways.) So, what we are actually concerned with, is the dialog of the cast, minus the occasional car (50 or 60 feet away from the cast, maybe even 80 feet away) zooming by. Well, some of this depends on how "loud" the noise is. We won't be able to cancel all of it, but some of it is bound to be useful. Think about it a second or three and I'm sure you'll agree. Being even a millisecond or so within synch isn't close enough. If I am within a millisecond, I am going to be doing a whole lot better than if I were doing it a quarter second off. It doesn't matter if you are time locked absolutely perfect to a femtosecond. That isn't the issue. The issue is that the sound at any two different points is guaranteed to be different, NOT JUST IN TIME, and therefore cannot be cancelled by simple subtraction. You are tilting at windmills. Once you have tried it and done a bit more serious study of the underlying issues, you will realize that you are playing a fools game. I expect to reduce the street noise to a manageable sound level, maybe one fourth the sound level of the cast. That means that not all of the noise can be subtracted out, but some of it ought to be subtractable. Inpossible. You will never get there. People with budgets 10000000 times more than you have been unable to do this. And not for lack of ideas or motivation. Actors who get paid millions and millions of dollars for a single film still spend tedious hours and hours shut up in ADR studios reproducing and re-recording their dialog in a quiet studio environment. If there were some way of eliminating this, do you REALLY think that someone wouldn't have discovered this method by now? Sorry to rain on your parade, but there are much more profitable things that you could be spending your time and resources on. |
#16
Posted to rec.audio.tech
|
|||
|
|||
Advice needed (was 'condensing water on microphones')
Richard Crowley wrote:
Im_Beta_00 wrote: Think about it a second or three and I'm sure you'll agree. Being even a millisecond or so within synch isn't close enough. If I am within a millisecond, I am going to be doing a whole lot better than if I were doing it a quarter second off. It doesn't matter if you are time locked absolutely perfect to a femtosecond. Time-locking it is what ruins it. Sheeesh. I suppose you are one of those people who can hear everything? I just want to erase the roar of the car, or at worst, detect the moment of the roar, and replace the relevant snip with a snip from a different microphone (one that is not pointed in the direction of the roar.) That isn't the issue. The issue is that the sound at any two different points is guaranteed to be different, Of course. NOT JUST IN TIME, I thought I just SAID that. and therefore cannot be cancelled by simple subtraction. It is not simple subtraction, and it isn't simple ANDing off the noise and ending up with some miraculously "clean" track. If you thought that was what I was getting at, I apologize. You are tilting at windmills. Once you have tried it and done a bit more serious study of the underlying issues, you will realize that you are playing a fools game. In terms of recording a few extra tracks (or "files"), redundancy always helps. The more backup recorders I have, the better. |
#17
Posted to rec.audio.tech
|
|||
|
|||
Advice needed (was 'condensing water on microphones')
Im_Beta_00 wrote:
Richard Crowley wrote: Im_Beta_00 wrote: Think about it a second or three and I'm sure you'll agree. Being even a millisecond or so within synch isn't close enough. If I am within a millisecond, I am going to be doing a whole lot better than if I were doing it a quarter second off. It doesn't matter if you are time locked absolutely perfect to a femtosecond. Time-locking it is what ruins it. Sheeesh. No. Time-locking is IRELLEVANT. I suppose you are one of those people who can hear everything? No. And furthermore you have not made a case for how that is relevant to anything?? I just want to erase the roar of the car, You simply cannot remove wideband noise without doing significant damage to the wideband signal of interest. Dunno how many different ways we have to say this before you can understand it? or at worst, detect the moment of the roar, and replace the relevant snip with a snip from a different microphone (one that is not pointed in the direction of the roar.) Lot of work for absolutely nothing. But apparently you will need to do the experiment for yourself since you refuse to learn from the mistakes of others. Good luck. If you have another mic picking up the signal of interest, but without the noise, then why not just use that one and dump the intrigue? It is not simple subtraction, and it isn't simple ANDing off the noise and ending up with some miraculously "clean" track. If you thought that was what I was getting at, I apologize. You have not mentioned any viable methodology of doing what you say you want to do. If you have some new secret scheme that you don't want to tell us about, then more power to you, go for it. But none of the techniques you have mentioned here are either new, unique, or proven effective. In terms of recording a few extra tracks (or "files"), redundancy always helps. The more backup recorders I have, the better. Absolutely. No question that redundancy is always good just in case something goes wrong. But it has nothing to do with noise reduction. |
Reply |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
NEVATON.EUROPE - RUSSIAN CONDENSER MICROPHONES | Marketplace | |||
Budget Condenser Microphones | Pro Audio | |||
A question about dynamic and condenser microphones and maths | Pro Audio | |||
Radio Shack "Vintage" Condenser Microphones... | Pro Audio | |||
FS: AKG C-501E / C-502E Electret Condenser Microphones, 3 Extra Capsules | Pro Audio |